Working with Light Sources

The information in this article applies to:

QUESTION

I know that I can use lighting to produce realistic 3D views of my work, but am not sure where to begin. Can you suggest some tips for working with light sources?

ANSWER

In Chief Architect, you can use light sources to help produce dramatic, photo-realistic 3D views of your model. To do so effectively though, takes an understanding of the different types of light sources available in the program, as well as practice.

There are three types of light sources in Chief Architect:

• Point lights, which emit light equally in all directions, similar to light bulbs.
  
• Spot lights, which emit a cone of light in a particular direction only.
  
• Parallel lights, which emit light in one direction, as though from a distant source like the sun.
  
  

For most interior lighting needs, Point lights are recommended because they are the most similar to electric light bulbs. 

In addition to the three types of lights in the program, materials can be given emissivity, allowing surfaces to appear to glow with their own light. This property can be very effective when applied to a TV or projection screen.


There are a variety of ways to add lights to a plan in Chief Architect.

To place lights

• Select Build> Electrical> Light  from the menu, then click at a location where you would like to place a light fixture.
  
  
• • If you click on a wall, a wall fixture will be created.
    
    
  • If you click away from a wall, a ceiling mounted fixture will be placed.
    
    
  • The default electrical objects that will be placed using this tool can be specified in the Electrical Defaults.
    
    
    
• Select View> Library Browser  from the menu:
  
  
• • Navigate to Architectural> Lighting and select a fixture.
    
    
  • When you move your cursor into the drawing area, it will display the Electrical  icon.
    
    
  • Click to place the selected library symbol in your plan. 
    
    
    
• Select 3D> Lighting > Add Lights  from the menu, then click to place a light without an associated 3D object.
  
  
• • Add Lights  lets you to customize the lighting in a space without adding electrical fixtures.
    
    

To edit lights

1. Select 3D> Create Perspective View> Full Overview  from the menu, then click and drag a camera arrow towards the light fixture.
   
   
2. Select 3D> Lighting> Toggle Shadows  while in the newly generated 3D view to toggle the display of shadows.
   
   
3. Click on the light symbol to select it, then click the Open Object  edit button.
   
   
   Note: If clicking the light symbol does not select it, make sure you have the Select Objects tool selected by pressing the space bar on your keyboard and then try selecting the light symbol again.
   
   
   
4. On the Light Data panel of the Electrical Service Specification dialog, click the drop-down arrow at the top of the dialog to see how many light sources are associated with this symbol.
5. 
   
   
   • Light fixtures can have any number of light sources associated with them.
     
     
   • Each light source can have its own unique settings and can be used in camera views, ray trace views, or both ("Use in Both").
     
     
     
6. With Light 1 (all views) selected as the current light source:
   
   
   • Click the Color box, select a color for the light, and then click OK.
     
     

     Selecting a distinct color, such as red or blue can help make changes to the light's settings more apparent in the 3D view.

      
   • Select the desired Intensity from the drop-down list. The options in this list correspond to commonly used light bulb wattages.
     
     
   • Select Custom from this list to open the Custom Light Intensity dialog. For the purposes of this exercise, we will uncheck Auto Adjust Intensity and experiment with the Intensity and Attenuated settings.
     
     
     
     
   • Click OK to close the dialog and apply your changes.
     
     
     

Now we will look at how adjusting some of these values affects the light in a plan.

In this example, a simple 15' x 15' square room is drawn, with a ceiling flush mounted light from the library placed inside it.

Notice how changing in the light's Intensity value affects the 3D camera view.

 

Next, recheck Auto Intensity, then repeat steps above, experimenting this time with the Attenuated values.

 

• Attenuation refers to how quickly the intensity of the light decreases as distance from its source increases.
  
  
• Small changes to the Attenuated values can have significant effects on the distance the light can travel.
  
  
  

To add a spot light

1. On the Light Data panel of the Electrical Service Specification dialog, select Light 1 (all views) and then choose Spot Light from the Source Type drop-down list.  
   
    
   
   
   
2. As with the intensity and attenuation, experiment with the Tilt Angle and Direction Angle.
   
   
   
   
   •  A Tilt Angle of -90° points straight down, while +90° points straight up.
     
     
   • A Direction Angle of 0° points to the right horizontally in floor plan view.
     
     
     
3. You can also experiment with the Cut Off Angle and Drop Off Rate.
   
   
   
   
   • The Cut Off Angle defines the angle of the cone of light created by a spot light and can be between 0 and 180 degrees.
     
     
   • The Drop Off Rate describes the rate at which the light intensity within the cone of light decreases.
     
     
   • When the Cut Off Angle is decreased, it is often a good idea to increase the Drop Off Rate.
     
     
     

Since multiple light sources can be applied to a single fixture, you can model the appearance of a chandelier, or the effects of directional track lighting.

To edit a fixture's multiple light sources

1. Click on the light fixture to select it, then click the Replace From Library edit button.
   
   
   
2. In the Replace From Library dialog:
   
    
   
   
   • Click the Library button, then browse to Architectural> Lighting> Track Lighting and select a fixture.
     In this example, the Basic 24" Track fixture is used.
     
     
   • Click OK to close both the Select Library Object and Replace From Library dialogs.
     
      
     
     
     
3. Click on the light fixture to select it, then click the Open Object edit button.
   
   
   
4. On the Light Data panel of the the Electrical Service Specification dialog:
   
   
   • Notice that there are five light sources associated with this fixture.
     
     
   • For the purposes of this example, Lights 4 and 5 have been deleted.
     
     
     
5. Select Light 1 (ray trace only) and click the radio button beside Use in Both so that this light source will display in rendered views that support lighting.
   
   
   • Make any changes to the settings for this light source.
     
     
   • As it is the only light source displaying in 3D views, it is easy to see its effects and make any needed changes.
     In this example, Light 1 has a Tilt Angle of -90 degrees.
     
     
     
6. Repeat this process with both Light 2 and Light 3.
   
   In this example, Light 2 has a Tilt Angle of -35° and a Direction Angle of 40° and Light 3 has a Tilt Angle of -20° and a Direction Angle of 320°. 
   
   
   
7. When all three lights are set up as desired, specify Use in Both for all of them and then see how they display when they are all enabled together.
   
    
   
   
   
   
8. If you want, you can check the box beside Show Position in Render View to display markers indicating the position of the light source in render views. 
   
   
   
   If the light source is a spot light, a directional arrow will display as well.
   
   
   
   

The Add Lights tool can be used to illuminate surfaces without creating electrical light fixtures in the plan.

1. Open a plan in which you would like to add a light source that isn't associated with a light fixture.
   
   
   • In this example, two directional spot lights will be used to highlight a painting.
     
     
     
2. Select 3D> Lighting> Add Lights from the menu, then click at a location where you would like to create a light source.
   
   
   
3. With the light source selected, click the Open Object edit button. 
   
   
   
4. In the Light Specification dialog:
   
   
   • On the Location panel, specify the needed height as the Absolute Elevation.
     In this example, 32" is used.
     
     
   • On the Light Data panel, specify the light Source Type as a Spot Light.
     
     
   • Click OK to close the dialog and apply your changes.
     
     
     
5. With the light source still selected, click the Copy/Paste edit button, then click beside the original to place a copy.
   
   
   
6. Use the Rotate edit handles that display at the end of each angle line and at the focal point to adjust the Direction Angle and the Cut Off Angle of each spot light.
   
   
    
   
   
   • In this example, the Direction Angles are moved to approximately 102 and 78 degrees, and the Cut Off Angles are both 112 degrees.
     
     You can check these values in the Light Specification dialog.
     
     
     
7. As you work with lights, you will often find that you need to make changes to their settings.
   
   After these lights are placed, their Attenuated values were edited:
   
    
   
   A point light was also added to this view, behind the camera, so that the spot lights aren't the only light sources in the view.
   
   
   

To use an emissive material

1. Use a digital image to create a custom material for display on a TV screen.
   
   
   
2. Select 3D> Create Perspective View> Full Camera , then click and drag a camera arrow towards the TV or projection screen.
   
   
   
3. In the 3D view, use the Material Painter  tool to apply the custom material to the screen surface.
   
   
   
4. Select 3D> Materials> Adjust Material Definition and click on the screen with your image.
   
   
   
5. Select the Properties panel, then move the Emissive slider to adjust this setting.
   
   
   
   
   

• Emissive controls how bright a material appears independent of the lighting in the scene. It can be used to simulate surfaces that are glowing with their own light, such as the glass on a light fixture. This option is only available for General and Reflective materials.
  
  
• For the purposes of this example, Emissive is set at 15% 
  
  

• When the desired Emissive value is set, click OK to apply this change.